Arthur Posted March 15, 2018 Posted March 15, 2018 No, not cryptic. Simply an assumption that as magnalium is a low strength alloy you would not be casting objects with it but preparing for making powdered magnalium for pyro purposes. I know someone who would make magnalium by melting the aluminium and putting solid magnesium in, in lumps. This formed the alloy, which he then poured into water to solidify it as roughly 4 mesh lumps, which he then ball milled. However once he had a flash fire as he opened the mill. I suspect that there will be a useful flux to cover the melt and reduce oxidation, the gold smelting industry uses borax which melts and floats on the metal and separates the impurities. Have a look in your country to see what flux is appropriate and available. wiki may help
memo Posted March 15, 2018 Author Posted March 15, 2018 (edited) I didn't have a good answer for you. I was using a 1 ton arbor press and I felt there was little danger. there was more danger melting it, Edited March 15, 2018 by memo
memo Posted March 15, 2018 Author Posted March 15, 2018 (edited) I don't ball mill my magnalium, but I do use a coffee grinder Edited March 15, 2018 by memo
stix Posted March 15, 2018 Posted March 15, 2018 (edited) Ok, thank you very much Arthur. I wouldn't be ball-milling the final product. If successful making magnalium, then I would crush using a hammer or similar then grade via screening. I'm hoping to achieve something around 80-100 mesh. I already have -325 mesh and have no desire or requirement to be ball-milling it to a finer grade. I appreciate your comments, I really do, but my question regarding "pressing" under "great" pressure, small pieces of Aluminium (ie. 2mm cubes) with small pieces of Magnesium shavings (2mm cubes) STILL hasn't been resolved!!!!!!!. I'm concerned that I'm loosing my mind. In every post I have asked if "pressing" under great pressure, could be a safety hazard. Given that there has been no satisfactory reply in that regard, then I must conclude that the common denominator is me, and therefore somehow I am unable to make myself clear. I certainly won't be proceeding with this experiment without advice. I think, for now I'll just have to put it on the "back-burner" - pardon the pun.... or I guess I could just use google. [EDIT] Cheers memo, I just saw your post. My concern is if under "great pressure" whether small pieces of each could/would exhibit spontaneous combustion like that may happen if ball-milling. I'll be pressing a 50/50 slug - then melting, then crushing and grading. Edited March 15, 2018 by stix
stix Posted March 15, 2018 Posted March 15, 2018 Anyways, I've gotta sign off now. I have to get up early tomorrow. I have an appointment to see my pyro-psychologist - there certainly will be lots to tell. Cheers.
Arthur Posted March 15, 2018 Posted March 15, 2018 "Great pressure" means different things to different people, so it's unlikely that any two people will agree on a definition. A puck made with a car jack press may be less well pressed than one pressed with a 20 - 20,000 ton press. Unless someone has actually done this particular pressing using the same tools as you intend to use then no-one has any proof of the safety of your system and you have to make some justifiable assumptions, then plan for the worst case and have a safe system of work and some safety guards and some PPE.
stix Posted March 15, 2018 Posted March 15, 2018 (edited) Unfortunately I don't know how much pressure. Lets just say that it's a "workshop" screw press about 5ft high with a huge cast iron & steel body. The screw itself is about 2 inches wide with a 2ft diam. round handle at the top. You can really lay on some serious pressures with it - but I don't have any figures. Is it conceivable that the pressure could cause ignition? - if no-one knows, then that's fine. I will not go there then. But it does seem like a nice way to consolidate the raw ingredients and therefore use some of the Mg turnings I have. Sort of like sintered but without the heat. The final slug will be melted. Edited March 15, 2018 by stix
Baldor Posted March 15, 2018 Posted March 15, 2018 Ignition when opening a ball mill jar is due to a lot of unoxidized surface being exposed to oxygen. It can happen with Al alone, no need for Mg. When you press the metal, you are doing the opposite, reducing the exposed surface. This is not advise from experience, only from theory, and may be wrong. I don't know if you have a PtoF gauge. If you have one, you can easily check the maximum force you can apply with the screw. Max force will depend on your arms if you don't use a cheater bar. I can tell you that with a 20cm radius handle and my arms, it's dificult to get over one ton with 1inch acme screw. (I'm a wimp)
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